In order to improve the analysis precision for thermal analysis on a printed circuit board, refined heat dissipation paths are important. Particularly, a printed circuit board having active parts (or heat-generating parts) within the board has most heat dissipation paths extending on the board surface and through an internal solid layer. Thermal modeling in consideration of heaters, wires, and VIAs within the board may be required.
In the prior art, analysis modeling has been performed by capturing parts (heat-generating or non-heat-generating), a layer configuration, wiring information, and VIA shapes from a printed circuit board CAD system through a CAD intermediate file. In order to reduce the scale of the analysis and for simplification, non-heat-generating elements have been modeled as follows:
Wiring pattern (in the horizontal direction): defined with an equivalent heat transfer rate on the basis of the wiring ratio of copper (Cu);
VIA (in the vertical direction): defined with an anisotropic heat transfer rate; and
Internal parts: defined with an equivalent thermal conductivity of a part.
The related prior arts are disclosed in the following documents:    [Patent Document 1]    Japanese Laid-open Patent Publication No. 9-230963    [Patent Document 2]    Japanese Laid-open Patent Publication No. 2006-91939    [Patent Document 3]    Japanese Laid-open Patent Publication No. 2008-91471